
package com.bstek.urule.model.function.impl;

import com.bstek.urule.RuleException;
import com.bstek.urule.Utils;
import com.bstek.urule.model.function.Argument;
import com.bstek.urule.model.function.FunctionDescriptor;
import com.bstek.urule.runtime.WorkingMemory;

import java.math.BigDecimal;
import java.util.Collection;


/**
 * @author Jacky.gao
 * @since 2015年7月22日
 */
public class AvgFunctionDescriptor implements FunctionDescriptor {
    private boolean disabled = false;

    public boolean isDisabled() {
        return disabled;
    }

    public void setDisabled(boolean disabled) {
        this.disabled = disabled;
    }

    @Override
    public String getName() {
        return "Avg";
    }

    @Override
    public String getLabel() {
        return "求平均值";
    }

    @Override
    public Object doFunction(Object object, String property, WorkingMemory workingMemory) {
        Collection<?> list = null;
        if (object instanceof Collection) {
            list = (Collection<?>) object;
        } else {
            throw new RuleException("Function[avg] parameter must be java.util.Collection type.");
        }
        BigDecimal total = null;
        for (Object obj : list) {
            Object pvalue = Utils.getObjectProperty(obj, property);
            BigDecimal a = Utils.toBigDecimal(pvalue);
            if (total == null) {
                total = a;
            } else {
                total = total.add(a);
            }
        }
        BigDecimal avgvalue = total.divide(new BigDecimal(list.size()), 12, BigDecimal.ROUND_HALF_UP);
        return avgvalue.doubleValue();
    }

    @Override
    public Argument getArgument() {
        Argument p = new Argument();
        p.setName("集合对象");
        p.setNeedProperty(true);
        return p;
    }
}
